I mean why waste money by by locks and destroy beauty and architecture of the place when you can simply buy her some snack with that money and as you mentioned go to petrin hill and eat it together haha prague is a beautiful city so any place is a romantic and beautiful places, rather than trying to leave a destructive mark try to enjoy it and make memories which are worth soo much more. Thanks for sharing this post and many of the people are going to be aware now from it. I know I wouldn’t do it and i hope to visit prague.